How Safe Is Your Shrimp?

Each of us eats, on average, almost 4 pounds per year, making shrimp more popular than tuna. Once considered a special-occasion treat, shrimp has become so ubiquitous that we now expect to find it on the menu whether we’re at a pricey restaurant or a fast-food joint.

In fact, Americans eat about three times more shrimp than we did 35 years ago. To satisfy our insatiable appetite, the U.S. has become a massive importer: About 94 percent of our shrimp supply comes from abroad, from countries such as India, Indonesia, and Thailand.

But our love affair with shrimp does have a downside. Most of the shrimp we import is “farmed”—grown in huge industrial tanks or shallow, man-made ponds that can stretch for acres. In some cases 150 shrimp can occupy a single square meter (roughly the size of a 60-inch flat-screen television) where they’re fed commercial pellets, sometimes containing antibiotics to ward off disease. If ponds aren’t carefully managed, a sludge of fecal matter, chemicals, and excess food can build up and decay. Wastewater can be periodically discharged into nearby waterways. “Bacteria and algae can begin to grow and disease can set in, prompting farmers to use drugs and other chemicals that can remain on the shrimp and seep into the surrounding environment,” says Urvashi Rangan, Ph.D., executive director of the Consumer Reports Food Safety and Sustainability Center. Those shrimp-farming practices raise a variety of concerns—not just about how safe shrimp are to eat but also about the environmental damage that can be caused by farming them that way.

For shoppers the dilemma starts at the grocery store, where it’s difficult to know what to buy. Labels and names can be confusing, meaningless, or—worse—deceptive. Sellers may not always tell (or even know) the truth about the origins of the shrimp they offer. And the allure of a label proclaiming that shrimp are “natural” or “wild” can obscure the fact that some expensive varieties aren’t necessarily fresher or more flavorful.

That’s why Consumer Reports decided to take an in-depth look at shrimp from a testing, tasting, and shopping viewpoint. We unearthed some worrisome findings, including bacteria on more than half the raw samples we tested and illegal anti­biotic residues on 11 samples. But there was also good news, in that there are plenty of healthful choices available.

There’s no foolproof way to make sure you won’t get sick from the bacteria on shrimp, but following our safe-prep rules will certainly improve your odds. And to make sure you’re buying the cleanest, most responsibly fished or raised shrimp—and that you’re getting what you pay for at the fish counter—use our guide on these pages.

What our tests showed: Bacteria and other problems

Despite America’s massive intake of shrimp, the Food and Drug Administration tested only 0.7 percent of foreign shrimp shipments last year. To do our own testing, Consumer Reports bought 342 packages of frozen shrimp—284 raw and 58 cooked samples—at large chain supermarkets, big-box stores, and “natural” food stores in 27 cities across the U.S. (We didn’t include fresh, never-frozen shrimp because they account for only a small percentage of the shrimp that consumers buy.)

(Photo: Getty Images)

We tested for bacteria such as salmonella, vibrio, staphylococcus aureus, and E. coli. We also looked for drug residues to see whether antibiotics were used in raising the shrimp. Antibiotics—none of which are approved by the U.S. for shrimp farming and which are illegal in imported shrimp—are problematic because their use can ultimately lead to bacteria becoming antibiotic-resistant, meaning that at some point the antibiotic may no longer work to treat common human ailments.

Our findings provided some cause for concern. In 16 percent of cooked, ready-to-eat shrimp, we found several bacteria, including vibrio and E. coli. Those bacteria can potentially cause illnesses such as food poisoning—which could include diarrhea and dehydration—and, in rare instances, can even prove fatal. In 11 samples of raw imported farmed shrimp, we detected anti­biotics. And in seven raw shrimp samples (six farmed and one wild), we found MRSA—methicillin-resistant staphylococcus aureus, a bacteria that can cause infections that are often difficult to treat.

Overall, 60 percent of our raw shrimp tested positive for bacteria, but it’s important to keep those findings in perspective. By comparison, in 2013, when we tested raw chicken breasts, 97 percent of the samples contained bacteria, says Rangan, who oversaw both the shrimp and chicken studies. Read “The High Cost of Cheap Chicken” for more details.

Compared with the chicken samples, far fewer shrimp contained salmonella, which is often responsible for outbreaks of food poisoning. But of concern, we found vibrio on many shrimp samples. “Vibrio is the most common cause of food poisoning from eating raw oysters,” Rangan says. “And even though most bacteria on shrimp would be killed during the cooking process, our test results raise real questions about how shrimp is raised, processed, and regulated.”

Dirty shrimp: What we found

Consumer Reports tested 284 samples of raw shrimp purchased at stores around the country and tested them for bacterial contamination. The last column shows the percentage of samples that contained at least one of the following bacteria: vibrio, staphylococcus aureus, E. coli, listeria, or salmonella—bacteria that can potentially make you sick. Our experts say more should be done to prevent contamination, but note that cooking should kill the bacteria.

(Photo: Getty Images)

Should you buy farmed shrimp at all?

The shrimp business can be extraordinarily lucrative when it’s done on a large scale. A medium-sized shrimp farm in Southeast Asia can produce close to a million pounds of shrimp per year—a powerful incentive for farmers to maximize production.

But evidence shows that those vast overseas operations may use antibiotics similar to those that humans rely on to treat infections. For example, they may use tetracyclines. Although many countries permit the use of antibiotics for shrimp farming, foreign shrimp destined for the U.S. market are not allowed to be raised using them and it is illegal to import shrimp containing them into this country. In addition, overseas shrimp farmers may also be using pesticides such as toxic organophosphates, and antifungals such as Gentian violet, which may cause cancer. Not only aren’t those chemicals permitted by the U.S. for shrimp farming, but they can also put your health at risk and damage the environment.

One reason farmers turn to antibiotics is that shrimp in crowded farms are extremely susceptible to diseases, such as Early Mortality Syndrome (EMS), which can wipe out entire harvests. In 2013, EMS was reported to have reduced Thailand’s shrimp output by 50 percent. But there’s a strange illogic here: According to Donald Lightner, Ph.D., a professor of veterinary science and microbiology at the University of Arizona, EMS doesn’t respond to antibiotics. In fact, our experts say that some of the most devastating shrimp diseases are caused by viruses, against which antibiotics don’t work.

It’s the FDA’s job to inspect shrimp coming into the U.S. to make sure it doesn’t contain any drugs or chemicals that aren’t permitted in imported shrimp. But in our tests, of the 205 raw farmed imported shrimp samples, 11 samples from Vietnam, Thailand, and Bangladesh tested positive for one or more antibiotics: Nine tested positive for oxytetracycline, three contained enrofloxacin, and two contained sulfa antibiotics. (Consumer Reports is calling on the federal government to make shrimp safer for American consumers.)

(Photo: Getty Images)

The contaminated samples were purchased at the following retailers in March, 2014: Albertsons, Costco, Fry’s Marketplace, Hy-Vee, Kroger, Sprouts Farmers Market and Walmart. (In nearly all cases we also purchased raw farmed imported shrimp from those outlets that tested negative for any antibiotics.) Consumer Reports is not alleging that any of the retailers from which we purchased the 11 raw farmed shrimp that tested positive for antibiotic residues violated any laws. It is the FDA, not local retailers, that is charged with enforcing the law that prohibits importing shrimp containing antibiotics.According to the FDA, if those drugs had been detected in even one shrimp sample, the entire shipment would have been refused entry into the U.S. Consumer Reports has shared our test results with the FDA and asked them to investigate (For more details about our test results, visit greenerchoices.org/shrimp.)

The small quantities of antibiotics we found probably wouldn’t affect a typical consumer’s health, says Michael Crupain, M.D., M.P.H., director of the Consumer Reports Food Safety and Sustainability Center. But farming shrimp with antibiotics has the potential to cause harm down the road: Antibiotics don’t kill off all bacteria, and those that do survive can multiply. If those resistant bacteria cause infections, certain antibiotics that once treated them will no longer work. What’s more, resistance can be transferred to other bacteria, including those that cause common human infections. In fact, the national Centers for Disease Control and Prevention estimates that antibiotic-resistant infections contribute to 23,000 deaths and more than 2 million illnesses in the U.S. each year.

We found the antibiotic-resistant bacteria MRSA on six samples of farmed shrimp from Vietnam, Bangladesh, and Ecuador, and on one wild sample from the U.S. MRSA can make you sick. “It’s spread through contact, so if MRSA gets on your skin while you’re preparing raw shrimp, it can potentially cause an infection, especially if you have an abrasion or cut,” Crupain says. MRSA causes serious skin and blood infections. And about 11,000 people in the U.S. die as a result of MRSA each year. We found more MRSA on shrimp than we found in our studies of pork, chicken, and ground turkey.

So which farmed shrimp should you buy? Consumer Reports recommends buying farmed shrimp raised without chemicals, including antibiotics. That can include shrimp farmed in large outdoor ponds that mimic the natural habitat or in tanks that constantly filter and recycle water and waste. Consumer Reports has evaluated organizations and stores that certify whether farmed shrimp—both domestic and imported—have been raised without drugs and chemicals. We recommend farmed shrimp labeled Naturland, Aquaculture Stewardship Council, or Whole Foods Market Responsibly Farmed. Another common certification is Best Aquaculture Practices, but we found antibiotics on four samples with that label.

Are wild shrimp a better choice?

One reason farmed shrimp is so popular is that it can be cheaper than wild shrimp, which is caught in the ocean. Our tests suggest that wild shrimp from U.S. waters may be worth the higher price. Of all the shrimp we tested, they were among the least likely to harbor any kind of bacteria or contain chemicals.

But it’s worth considering the environmental implications of going wild. According to Amanda Keledjian, a marine scientist at the nonprofit conservation group Oceana, “Nets dragged along the ocean floor can severely damage the sea bottom and anything that lives there.” Estimates vary, but at least 1 to 3 pounds of other species—including endangered sea turtles—can be killed for every pound of shrimp caught in the wild. To minimize the impact, a U.S. federal law requires shrimpers, with some exceptions, to outfit their nets with devices that allow other sea life to escape. But, says Rangan, “A law on Louisiana’s books prohibits the enforcement of those rules.”

Still, when it comes to safety and sustainability, responsibly caught U.S. wild shrimp is our top choice. Consumer Reports recommends buying wild shrimp certified by the Marine Stewardship Council, an organization that ensures shrimpers are fishing responsibly; shrimp from Whole Foods Market; and those listed as “Best Choices” or “Good Alternatives” on Monterey Bay Aquarium’s Seafood Watch Guide, at seafoodwatch.org. Read more about the shrimp labels you can trust.

Which tastes better—wild or farmed?

Shrimp connoisseurs, from celebrity chefs to seasoned shrimpers, claim to detect a striking difference between wild and farmed shrimp, and there’s some science to support their claims. The CSIRO Division of Food Science and Technology in Sydney, Australia analyzed wild and farmed shrimp to investigate why they can taste different. Sure enough, wild shrimp had far higher levels of compounds called bromophenols, which the researchers equated with a “briny, oceanlike” flavor.

But don’t assume that briny means better. To conduct a small tasting, Consumer Reports purchased 24 packages of seven types of frozen shrimp from Whole Foods Markets near our Yonkers, N.Y., headquarters. They included Atlantic white, Key West pink, and Gulf white shrimp, all caught in the U.S., as well as farmed shrimp from Thailand, Ecuador, and Vietnam. Sizes varied, but the difference in price was startling; it ranged from $10 per pound for farmed shrimp from Ecuador to $19.99 per pound for wild-caught Gulf white shrimp and wild-caught Key West pink shrimp.

Overall, our tasters found very little difference between the farmed and wild shrimp. But they did note that some wild shrimp had a taste of iodine—a flavor that our experts say is probably due to higher levels of bromophenols. The intensity of that flavor varied; it was stronger in shrimp from the Gulf of Mexico and milder in shrimp from the Florida Keys and the Atlantic.

“Nutritionally, whether you choose wild or farmed shrimp, they pack the same major nutrients,” says Amy Keating, R.D., a nutritionist at Consumer Reports. In a 3-ounce serving of cooked shrimp, you’ll get 101 calories, 19 grams of protein, 1 gram of fat, and 179 milligrams of cholesterol, making shrimp a healthy, low-fat source of protein.

Can you trust the labels on shrimp?

Not always. “If a shrimp label says ‘Organic,’ ignore it,” Rangan advises. “There are no U.S. standards for the organic label when it comes to seafood, unlike for produce and meat.” The same goes for labels proclaiming that a package of shrimp is “Natural” or “Environmentally Aware.” We also picked up a bag of shrimp labeled “Chemical-free” (a claim that is not regulated), which tested positive for the antibiotics oxytetracycline and sulfamethoxazole. “Antibiotics are chemicals,” Rangan says. “Producers should be honest about how their shrimp is raised.”

The Department of Agriculture requires supermarkets and warehouse clubs to state whether shrimp is wild or farmed, along with its country of origin. But a 2014 Oceana study found that even those common classifications can be inaccurate. Oceana bought 143 shrimp samples from 111 vendors nationwide and ran DNA tests to figure out exactly what type, or species, they’d purchased. It turned out that 30 percent of the labels were misleading in some way. For example, in some cases farmed white-leg shrimp (the most commonly farmed shrimp globally) were sold as wild shrimp. “This is seafood fraud, especially given the far higher price of wild shrimp,” says study author and senior scientist Kimberly Warner, Ph.D. Oceana even found a small banded coral shrimp, which is not meant to be eaten, mixed into a bag of salad-sized shrimp.

How can a consumer make smart choices given those shady shrimp sellers? Marianne Cufone, an environmental attorney and executive director of the Recirculating Farms Coalition, says there are some clues that might help you distinguish wild from farmed. “Wild shrimp often vary in size, shape, and color because they don’t all have identical genetics,” she says. “Batches of farmed shrimp often all hatch at the same time, eat the same food, and live in the same environment, so they’re more likely to look the same.” Cufone’s second tip: “Look for poop, or what is politely called a vein.” Frequently, shrimp farmers stop feeding shrimp before harvesting them so that the vein empties. If you see a dark line, there’s a better chance it’s a real wild shrimp.

Is ‘fresh’ or frozen better?

Another confusing choice for consumers is whether to buy the frozen shrimp you see in bags or the “fresh” shrimp at the seafood counter. If you’re buying from a gourmet seafood store or seaside market, you may find actual fresh shrimp, but the truth is that most shrimp you encounter in supermarkets have been frozen soon after they are caught, before they are shipped to stores. So there’s a very good chance that the glistening tray of shrimp at the seafood counter in your store was previously frozen, then thawed. “In fact,” says Steven Wilson, deputy director of the NOAA Fisheries Office of International Affairs and Seafood Inspection, “it could be the same shrimp that’s in the freezer case—just defrosted.”

Raw or cooked?

According to a 2015 Consumer Reports National Research Center survey of 1,015 U.S. adults, more than a quarter of buyers prefer their shrimp precooked. Though buying cooked shrimp may be convenient, it does not guarantee safety. In our tests, we found concerning bacteria, including vibrio and staphylococcus aureus, in a few of our cooked samples. If you want to be extra careful, you can buy raw shrimp, handle it properly, and cook it yourself to kill any bacteria. Read more about how to safely clean shrimp.